Amongst devices of the same variety as the present device, devices which mark on a first coordinate axis the carbon dioxide concentration in air breathed by a subject, and mark on a second coordinate axis ventilation volume from the subject breathing, and display a pattern representing the relationship between the carbon dioxide concentration and ventilation volume on a coordinate plane formed from the first coordinate axis and the second coordinate axis, are well-known (for example, Japanese Laid-Open Patent Publication No. 2011-45592, hereafter referred as Patent Document 1). From such devices, the condition of the lungs of a subject can be diagnosed from the shape of the pattern displayed.
The abovementioned pattern representing the relationship between carbon dioxide concentration and ventilation volume form a hysteresis loop which closes with each respiration cycle from the subject (a cycle consisting of one exhalation and one inhalation). Accordingly, in order to display said relationship of the next respiration cycle, it is necessary to erase the hysteresis loop which was originally formed for the display of a new hysteresis loop to begin, or a new hysteresis loop has to be displayed by overwriting the hysteresis loop which was originally formed. Therefore, it is difficult to ascertain trends for said relationship (changes in each respiration cycle), and there is a burden being placed on medical practitioners.
Considering the above situation, the purpose of the present invention is to provide a technique which reduces the burden on medical practitioners by displaying the relationship amongst a plurality of respiration parameters.